The route of the controversial HS2 rail project may be torn up if the
Government’s airport commission calls for the expansion of Heathrow.

Patrick McLoughlin, the new Transport Secretary, has signalled that he could reroute the new high-speed train line towards Heathrow if the aviation inquiry recommends developing the west London airport.

Such a move would represent a dramatic U-turn for the Government and be hailed as a triumph for campaigners seeking to protect part of the Chilterns, an area of outstanding natural beauty, included in the route. There has been heavy opposition to the proposed route for HS2, between London and the North, since it was unveiled by Justine Greening, Mr McLoughlin’s predecessor, in January.

Despite criticism from a host of Conservative MPs, including David Lidington, the Europe Minister, and Cheryl Gillan, the former Welsh Secretary, the Government has until now remained wedded to a route taking HS2 through the wooded vales of Buckinghamshire and Oxfordshire.

Only last month officials working on HS2 told The Sunday Telegraph: “The route that was agreed by the Transport Secretary in January is the one that we believe gives the best balance between cost, benefits and sustainability.” However, Mr McLouglin has now said that HS2 may have to be “adapted” depending on what Sir Howard Davies, the economist leading the Government’s airport commission, says about Heathrow. “I hope if anything needs to be adapted we will have time to do it,” he said.

Last night aides acting for the Transport Secretary stressed they would not “prejudge” the findings of the Davies Commission. However, they made clear that HS2’s route could be redirected towards Heathrow if the economist recommended expanding the airport.

Although support for developing Heathrow has grown at Westminster in recent months, the Davies Commission will consider a number of alternatives, including a new airport in the Thames estuary, a project dubbed “Boris Island” because it has the backing of Boris Johnson, the London Mayor.

If the HS2 line is rerouted towards Heathrow, it will probably go to the west of the Chilterns. Mr McLoughlin’s words offer hope to thousands of homeowners along the proposed route, many of whom have already seen the value of their homes fall by as much as 40 per cent since the route was announced.

Estate agents say many properties along the line are not selling at any price even though work on the London to Birmingham stretch is not set to begin until 2018.

The Davies Commission is not expected to report until 2015. Such a late change to HS2’s route would put officials in charge of the project under great pressure and almost certainly delay the scheme.

The directors of HS2 Ltd, the quango set up to deliver the scheme, have admitted they are finding the timetable set by ministers “very challenging”. Officials are struggling to inspect the land and complete all the design work in time to lay the hybrid Bill before Parliament next year.

The most recent boardroom minutes of HS2 Ltd stated: “It was agreed that the time-frame [to deliver the hybrid Bill] was very challenging and that the board agenda will be set so as to allow progress to be monitored closely.”

Mr McLoughlin did not make clear how much of HS2’s route could be “adapted”. The architect of Britain’s only other high-speed rail network last month said that HS2 should run via Heathrow and in a corridor close to the M40 motorway.

Mark Bostock, who developed the Channel Tunnel rail link between Dover and London, said this alternative path would reduce damage to the environment.

It would also be more sensible to connect HS2 to Heathrow airport, he said.

However, HS2 recently said: “An M40 route would cost £3billion more and affect more population centres, including Gerrards Cross, Beaconsfield, High Wycombe and Princes Risborough, which have a combined population in excess of 110,000 people.”

A possible change in the route is the latest headache for directors of HS2. In December a High Court judge will consider applications by five groups to force the ministers to rerun their initial public consultation.

If the judicial review goes against the Government, the project could be delayed by as much as two years.

Civil servants have advertised for private contractors to oversee new consultations after more than 11,000 submissions to the initial exercise last year went astray.

One of the tender documents states that the new contract — worth up to £6million — is to run a “range of different consultations” but admits that the “precise forward programme of consultations is not known at this stage”.

A senior official at the Department for Transport stressed that the Government still hoped to win the judicial review and that it felt it had a “robust” case.

A spokesman for the department said: “There is a large amount of engineering design and environmental assessment work that has to be done in preparation for depositing the hybrid Bill in Parliament towards the end of 2013.

“There is also a significant programme of stakeholder engagement and public consultations that needs to be undertaken. We remain on course to introduce the Bill by the end of 2013 as has always been the plan.”